Steam Oven Drain Time Control Without Water Level Sensors

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Solution Overview

Problem

Cooking ovens using steam do not inform users of the draining time of the hydraulic circuit based on the quantity of water contained, leading to uncertainty and increased costs due to the use of water level measuring devices.

Innovation Solution

A control method that determines the emptying time of the hydraulic circuit by measuring the water consumption of the steam generator and displaying it to the user without the need for a water level measuring device, using a predetermined water quantity and operating parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If a water level measuring device is installed in the hydraulic circuit to measure water quantity, then the user can be informed of the water level evolution during draining, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvewater level informationVSAvoiddevice complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent uses an intermediary approach by measuring a parameter that correlates with water level (voltage from a voltage divider circuit involving a float and variable resistor) rather than directly measuring water level with a complex dedicated sensor. This intermediary measurement system provides sufficient information while keeping the device simple and cost-effective.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces complex mechanical water level measurement devices with an electrical measurement system. A float mechanism combined with a variable resistor creates a voltage signal that electronically represents water level, eliminating the need for complex mechanical level sensors or switches.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Loss of information

If a water level measuring device is installed to provide real-time water level information, then the user can monitor the draining process, but the manufacturing cost increases

Engineering Contradiction:
Improvewater level informationVSAvoidmanufacturing cost
Core Design Contradiction:
Loss of informationVSEase of manufacture

Solution Approach 1:

The patent employs inexpensive components (float, variable resistor, voltage divider circuit) that are cheap and easily replaceable, rather than using expensive dedicated water level sensors. This approach significantly reduces manufacturing cost while providing the necessary functional capability.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The variable resistor serves multiple functions: it acts as both a mechanical stop for the float and an electrical sensor element. This multi-functionality reduces the total number of components needed, lowering manufacturing cost and complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Loss of information

If the draining time is not displayed to the user, then the control system remains simple, but the user lacks information about the emptying duration

Engineering Contradiction:
Improvedraining time informationVSAvoidcontrol system complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The control unit pre-calculates and stores the draining time based on the measured water quantity and the known drain pump flow rate. This preliminary calculation allows the system to display accurate draining time information without requiring complex real-time monitoring and calculation during the actual draining process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system provides feedback to the user by displaying the calculated draining time on the control panel. This feedback mechanism informs users about the emptying duration without requiring complex real-time measurement systems, as the time is derived from pre-established relationships between water quantity and drain pump performance.

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Informs users of the draining time and reduces the cost of the oven by eliminating the need for a water level measuring device, providing a cost-effective solution for determining water consumption and emptying duration.

Implementation Method 1

a steam generator supplied with water from said hydraulic circuit and producing steam to be diffused into said cooking cavity

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

a drain pump, characterised in that the control unit determines a duration of emptying as a function of the quantity of water consumed by the steam generator and of a predetermined quantity of water for filling the hydraulic circuit with water

Methodology Applied
Scientific EffectPumping: Pump

Data Source

PatentEP2409571B1Method for controlling an operating furnace by using steam and associated furnace
Publication Date: 2013.09.11 FAGORBRANDT
  • EP2409571B1 patent drawingFigure 1
  • EP2409571B1 patent drawingFigure 2
  • EP2409571B1 patent drawingFigure 3

AI summary

The method involves filling a hydraulic circuit (17) of cooking oven (1) with predetermined quantity of water. Quantity of water consumed by a vapor generator (11) is determined during execution of operating cycle of the cooking oven. Draining duration of the hydraulic circuit is determined by a control unit (10) based on the quantity of water consumed by the vapor generator and the predetermined quantity of water filled in the circuit, where the control unit controls operation of the vapor generator. The draining duration is displayed by a display unit i.e. LCD, of control panel (7). An independent claim is also included for a cooking oven comprising a cooking cavity.